Electrical Machine System With Planetary Gear Coupling

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Solution Overview

Problem

Existing electrical machine systems with multiple rotors face challenges such as complex stator geometries, inefficient torque distribution, and high material costs due to the need for precise mechanical production and additional stator components, especially when trying to achieve opposite directions of rotation at the same speed and three-phase current topologies.

Innovation Solution

A compact electrical machine system with mechanically connected sub-machines via a planetary gear, where magnetic flux components are compensated to reduce magnetic material usage and allow for a simplified design, enabling the use of a mechanical coupling that saves components and reduces gear losses by having only one contact point per planet gear, and allowing for a three-phase current winding system with reduced coil count.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple rotors are arranged in a matrix configuration with common stator, then torque distribution is improved, but stator geometry becomes complicated and manufacturing precision requirements increase

Engineering Contradiction:
Improvetorque distributionVSAvoidstator geometry
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The stator is divided into multiple independent pole pairs, each serving a specific rotor. This segmentation allows each stator pole pair to be designed and manufactured independently, reducing overall geometric complexity while maintaining effective torque distribution across multiple rotors

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The common stator structure serves multiple functions simultaneously: it provides magnetic poles for multiple rotors, establishes the three-phase current topology, and enables synchronized operation. This multi-functionality reduces the need for additional components and simplifies the overall system geometry

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If adjacent rotors rotate in opposite directions at the same speed, then mechanical coupling efficiency is improved, but gear stage complexity increases

Engineering Contradiction:
Improvemechanical coupling efficiencyVSAvoidgear stage
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Instead of using complex differential gear mechanisms to achieve opposite rotation directions, the invention inverts the approach by directly coupling adjacent rotors through the magnetic field. The rotors naturally rotate in opposite directions due to the three-phase current topology and magnetic field interaction, eliminating the need for additional gear stages

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The mechanical gear coupling is replaced by direct magnetic field coupling between rotors. The electromagnetic interaction provides the necessary torque transmission and direction control without mechanical gears, reducing complexity while maintaining coupling efficiency

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If fully developed stators are assigned to each rotor, then magnetic flux compensation is improved, but material costs and manufacturing precision increase

Engineering Contradiction:
Improvemagnetic flux compensationVSAvoidmagnetic material
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

Multiple stators are merged into a single common stator structure that serves all rotors. This consolidation maintains the necessary magnetic flux compensation through proper pole pairing while significantly reducing the total quantity of magnetic material required compared to having separate stators for each rotor

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Different regions of the common stator are designed with locally optimized properties to serve specific rotors. Each pole pair within the common stator is configured with appropriate magnetic characteristics for its associated rotor, maintaining effective flux compensation while reducing overall material usage

Inventive Principle:
Principle #3Local quality

4Power

If conventional planetary gear with multiple planet gears is used, then torque distribution is improved, but manufacturing precision requirements and cost increase

Engineering Contradiction:
Improvetorque distributionVSAvoidmechanical production
Core Design Contradiction:
PowerVSManufacturing precision

Solution Approach 1:

The conventional planetary gear mechanism is replaced by direct electromagnetic coupling between rotors through the common stator. This substitution eliminates the need for precise mechanical manufacturing of planet gears while maintaining effective torque distribution through the magnetic field interaction

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design achieves a more economical and efficient machine system with reduced mechanical losses, enabling higher power installation in the same volume with lower peripheral speed, and allows for the same performance with half the peripheral speed, while simplifying the mechanical realization and reducing material costs.

Implementation Method 1

adjacent sub-machines having opposite directions of rotation at the same rotational speeds

Methodology Applied
Scientific EffectGear: Gear

Implementation Method 2

magnetic flux components from adjacent sub-machines are compensated for piecemeal

Methodology Applied
Scientific EffectMagnetic flux compensation: Magnetic Field

Implementation Method 3

electrical machine system with an even number of mechanically and electrically coupled sub-machines

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3479462B1Electrical machine system
Publication Date: 2020.12.30 VIENNA UNIVERSITY OF TECHNOLOGY
  • EP3479462B1 patent drawingFigure 1~2
  • EP3479462B1 patent drawingFigure 3~4
  • EP3479462B1 patent drawingFigure 5~6a

AI summary

The invention relates to an electrical machine system having mechanically and electrically coupled partial machines (1-4) that have common magnetic sections and common coils (for example, u1, 2), and are connected by means of a mechanical gear mechanism, wherein adjacent partial machines (1-6) have opposite directions of rotation to one another when rotating at the same rotational speeds, and the mechanical coupling is defined by a gear function that simultaneously defines the transmission ratio of the rotational speed of the rotor to the rotational speed of the gear output.